Rule 3e regarding auctions has been edited today to provide more clarity in regard for bid delays:

e. No delaying/postponing auctions-auctions must end with the highest bidder if no one else bids after a few minutes.

If you set a time limit for your auction, 'last call' bids are to be done within the time limit you originally set. This means no adding on time or going over your time limit to get last minute bids. If this is a problem for you, you can stop placing time limits on your auction and instead end it when people stop bidding after a few minutes.

This was a requested edit in response to the increase of people intentionally dragging on auctions past their declared time to rake in more bids.